Fig. 1

Determination of lymphovascular invasion (LVI) by hematoxylin and eosin (HE) staining and double immunohistochemistry (D-IHC) A Vascular invasion (red arrow, HE). B Venous invasion (red arrow) adjacent to an isolated artery (green arrow) (HE). C Lymphatic vessel invasion (red arrow, HE). D Lymphovascular invasion is indefinite (HE). E Vascular invasion (CD31 + CK (AE1/AE3) D-IHC). The blue arrow shows the presence of tumor cells (red color) in the lumen with endothelial cells positive (brown color) for CD31. F Vascular invasion (D2-40 + CK (AE1/AE3) D-IHC). The endothelial cells of the vessel are negative (blue arrow) for D2-40. G Lymphovascular invasion is indefinite (HE). H Lymphatic vessel invasion (D2-40 + CK (AE1/AE3) D-IHC). The blue arrow shows the presence of tumor cells (red color) in the lumen with endothelial cells positive (brown color) for D2-40. I Lymphatic vessel invasion (CD31 + CK (AE1/AE3) D-IHC). The endothelial cells of the vessel are negative (blue arrow) for CD31. All images are magnified 200 ×